Biology 1 V23: 2.04 Lilith M. Jessie
Sat, Nov 6 - 2021
Cell Transport lab

Objective(s): “Eggs are a great example of a cell. Underneath the hard shell is a thin membrane that is just like the cell membranes in other cells. Remember that the function of the cell membrane is to control the internal balance of the cell. It helps to maintain homeostasis.”

Hypothesis: I Hypothesise that egg#1 will expand, as egg#2 will stay the same.

Variables:
Independent Variable: the vinegar and water
Dependent Variable: the eggs
Controlled Variable: the jars placed on the window ledge

Materials:
Raw egg
String or thread or yarn
Ruler
White vinegar
Tap water
Jar with lid (like a mayonnaise jar or something big enough to put the egg in)

Procedures:
Before beginning the experiment, record at least two observations of the raw egg in your lab report.
Wrap the string around the center of the egg to determine its initial circumference. Measure the string and record the initial circumference in centimeters (cm).
Gently wrap the egg in the jar and completely cover the egg with vinegar. Use the lid to seal the jar and note the time. This will be considered the "start time" of the experiment.
After approximately 24 hours from the start time, carefully remove the egg from the jar of vinegar. If the shell has completely dissolved, exposing the inner membrane, move on to the next step. If not, return the egg to the vinegar until the shell has completely dissolved.
Record at least two observations of the egg.
Measure and record the circumference of the egg, being sure to measure it in the same way every time you measure circumference.
Pour out the vinegar and rinse the jar. Then fill the jar about half full of tap water.
Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
After a total of 48 hours from the start time, carefully remove the egg from the jar of water.
Make two observations of the raw egg, and measure and record the circumference.
Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
After a total of 72 hours from the start time, carefully remove the egg from the jar of water.
Make two observations of the raw egg, and measure and record the circumference.

Data and Observations:
Record your observations from the experiment either the hands-on lab or the teacher led video. Don't forget to include at least two detailed observations and the measurement of the egg's circumference in centimeters.
Time (hrs)
Observations
Circumference (cm)
0
The egg is small
The egg is small
5⅜in/ 160.02cm
5⅜in/ 160.02cm
24
The egg became a bit more puffy and more squishy like rubber
This egg stayed the same, the eggs hard shell is the same
6in/15.24cm

5⅜in/ 160.02cm

48
Still the same, but a little murky.
The hard shell of the egg is still the same as before
6in/15.24cm

5⅜in/ 160.02cm

72
Same as before, but once the egg popped it leaked slowly out one piece after another.
The same
6in/15.24cm

5⅜in/ 160.02cm

Conclusion:
Be sure to answer the following reflection questions as a summary in the conclusion of your lab report:
Was your hypothesis correct? Why or why not?
How much did the egg change in size? (answer should be in centimeter)
Evaluate the lab and data collected. What type of transport occurred in this lab? Explain your answer, including evidence from your experiment to support your explanation.

Questions:
Using what you have learned in the lesson and the experiment, answer the following questions in complete sentences.
Consider how lettuce or spinach placed in water becomes firm and crisp. Use what you have learned about cell membranes to explain this observation. Be sure to include homeostasis in your explanation.
If you were to continue this experiment by removing the egg from the water and covering it in corn syrup (a hypertonic solution), what do you think would happen? Explain your prediction. (If you choose to test your prediction, be sure to allow at least 24 hours before making your observations. And, of course, handle the egg very carefully!)
Equilibrium is when the concentration is the same throughout and entire system. Explain how a cell reaches equilibrium in all three types of solutions (hypertonic, hypotonic and isotonic).